This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. There is significant interest in the development of novel non-invasive techniques for the diagnosis of Alzheimer disease (AD) and tracking its progression. Because magnetic resonance imaging (MRI) is non-invasive and routinely performed in the setting of neurological disease, implementation of new MRI-based techniques for the diagnosis and prognosis of AD are especially advantageous. Since sodium (23Na) MRI has been shown to be sensitive to cell death and viability, we tested whether early changes would be seen in Alzheimer disease, a disease where neural cell death has been well established.For these studies we compare measurements made with sodium MRI with conventional brain scanning in age-matched participants with and without AD. We also measure sodium measures on brains willed to us from deceased AD patients and compare that with histologic measures of disease. So far we have demonstrated differences in sodium MRI that seem to correlate better with the presence of mild AD than conventional markers. Ongoing studies hope to reproduce this effect in larger groups of patients and further understand the underlying mechanism of this phenomenon. It is hoped that with further study sodium MRI may be a useful tool for the quantitative diagnosis and disease tracking of AD.